A variety of fasteners are used in orthopedic surgical procedures to secure bone fragments, reattach ligaments or soft tissue to bones, or to stabilize bones in relative position to one another. For example, cervical plates are typically secured to vertebrae with bone screws to stabilize the cervical spine Likewise, occipital plates are typically secured to the back of the skull with bone screws for attaching spinal rods. Pedicle screws are inserted into the pedicle of a vertebral body and are commonly used along with rods and screws to immobilize a portion of the spinal column. In other applications, pedicle screws are inserted into a series of vertebrae and one or more metal rods are secured to the heads of the screws, typically using set screws or some other securing means.
Many orthopedic screw designs require multiple steps to insure proper implantation into bone. Typically, an entry point is made in the bone using a high speed drill bit to create a pilot hole. The pilot hole may then be probed with an instrument to detect any breaches in the bone wall. After the integrity of the bone wall is confirmed, the pilot hole is then tapped to create a track in the bone wall for the orthopedic screw to follow using a tap. Finally, the screw may be implanted into the prepared hole. Others procedures involve driving self-tapping screws into pre-drilled pilot holes. Still other procedures involve driving self-drilling screws directly into the bone without pre-drilling or pre-tapping.
Procedures which require multiple steps can create the potential for the patient to experience complications with each step. Additionally, the chances for a surgeon to make a mistake due to fatigue during long procedures involving multiple screws increases with the number of steps required for placement of each screw. Thus, there is a need for an improved orthopedic screw that reduces the number of steps required for implanting the screw into bone.